Comment: Small valves make a big difference in operations

The importance of valves in the industry

Pressure reducing valves (PRV) are central to oil and gas production, keeping pressure within the very strict parameters required at all times. And this pressure regulation is especially important in onshore operations, where oil or gas may need to be transported at several different pressures at different stages of the process. 

Yet despite how essential PRVs are not just to oil and gas operations, but to myriad industrial processes, selecting a valve to use can often feel like an exercise in assessing the least-worst option. For example, while the traditional diaphragm valve patented by Bryan Donkin in the Victorian age is cheap to operate, it is also prone to failure as the elastomers that enable the device eventually succumb to fatigue, erosion and embrittlement as a result of the very high pressures. And while actuated ball valves are undeniably efficient, they also require a hugely expensive uninterruptable power supply in order to ensure safe and reliable operation. 

In contrast, the devices being introduced to the market by Oxford Flow manages to hit the advantage of being as efficient as it is cost-effective. 

Created in the labs of Oxford University’s Osney Thermo-Fluids Laboratory, the innovative technology was created in the course of Oxford Professor Thomas Povey’s research into heat transfer in jet engines, after he found his work limited by the fact that no existing PRV was capable of withstanding the very high pressures he needed to use in the course of his experiments. 

Not one to shy away from an engineering challenge, Povey returned to ‘engineering first’ principles and designed a valve that used a piston to regulate pressure rather than a diaphragm. 

Replacing the diaphragm with a piston 

In the Oxford Flow model, the diaphragm is replaced by a direct sensing piston actuator. One side of the piston is exposed to the downstream pipeline pressure, while the other side is balanced against a pressure cavity controlled by a pilot regulator. During operation, the piston moves inward, reducing the size of the cavity when the downstream pipeline pressure exceeds that within the pressure cavity set by the pilot regulator. 

The movement of the piston actuator in closing reduces the flow rate to maintain a stable downstream pressure. As demand increases, the downstream pressure falls below that set by the pilot and the reverse operation occurs. 

Improved performance

Testing demonstrated that in addition to being a more efficient and reliable way of regulating pressure, this piston-led technology also brings with it a host of other benefits, including reduced hunting, lower noise emissions, minimised flow turbulence and reduced minimum pressure head-drop. 

Other advantages include just one moving part, which means the Oxford Flow valve is much better placed to handle ‘dirty’ or corrosive substances and is less likely to malfunction. This in turn reduces repair and replacement costs, meaning Oxford Flow devices have an ultra-long service schedule when compared to other valves in the market. And because they’re also self-powered, self-regulating and self-controlling, and smaller and lighter than their competitors, both running costs and installation costs are also significantly lowered.

More good news for businesses is that adopting the devices will not necessitate wholesale replacement of infrastructure. Oxford Flow’s technology can also be easily retrofitted into existing pipelines, and is simple to fit into the current strainers and filters used in the sector. For example, the IM Series wafer-type and IHF Series can both be installed between PN and ANSI flanges.

The use of these valves can not only contribute to much more reliable and efficient operations for oil and gas businesses operating in the Middle East, but it can also help lower costs too. And in a market in which profit margins are consistently under pressure, that can only be a good thing.